Experimental teaching is an important part of postgraduate training in basic and clinical medicine. While primary cell isolation and identification are among the most important research techniques for medical graduate students, most graduate students do not understand and master these techniques before starting their research experience. In particular, many students lack training in this field, and high-quality teaching and learning materials are still very sparse. Here, we designed a practical experiment course for graduate students engaged in research. The target students usually have research projects involving primary cell culture in their future research, making the course highly applicable for the students. The lab exercise focused on the methods of primary cell isolation (including mechanical grinding method, explant culture method and enzymatic digestion method) and identification (including flow cytometry, immunofluorescence, and periodic acid-Schiff (PAS) staining). It aimed to help students master the conceptual, principle, technical, operation, and analytical skills related to primary cell culture and contributed to their foundation for future research. Students generally reflect that they have initially mastered the isolation and identification of primary cell culture as a result of the course. Student feedback also indicates significantly increased confidence in the practical application of primary cell culture in the future. Here, we provide our experience for others who may want to implement similar courses.

DNA interstrand crosslinks (ICLs) are extremely deleterious lesions that are repaired by homologous recombination (HR) through coordination of Fanconi anemia (FA) proteins and breast cancer susceptibility gene 1 (BRCA1) product, but the exact role these proteins have remains unclear. Here we report that FANCG was modified by the addition of lysine63-linked polyubiquitin chains (K63Ub) in response to DNA damage. We show that FANCG K63Ub was dispensable for monoubiquitination of FANCD2, but was required for FANCG to interact with the Rap80-BRCA1 (receptor-associated protein 80-BRCA1) complex for subsequent modulation of HR repair of ICLs induced by mitomycin C. Mutation of three lysine residues within FANCG to arginine (K182, K258 and K347, 3KR) reduced FANCG K63Ub modification, as well as its interaction with the Rap80-BRCA1 complex, and therefore impeded HR repair. In addition, we demonstrated that K63Ub-modified FANCG was deubiquitinated by BRCC36 complex in vitro and in vivo. Inhibition of BRCC36 resulted in increased K63Ub modification of FANCG. Taken together, our results identify a new role of FANCG in HR repair of ICL through K63Ub-mediated interaction with the Rap80-BRCA1 complex.

Gallbladder carcinoma (GBC) is a malignancy with an extremely poor prognosis. In order to improve the survival rate, identification of new susceptibility risk factors is of importance. Here, we report findings on the novel cancer-related gene lysosomal protein transmembrane 4 beta (LAPTM4B) that has two alleles designated LAPTM4B*1 and LAPTM4B*2. Allele *1 differs from allele *2 in that it contains one copy of a 19-bp sequence, whereas this sequence is duplicated in exon 1 of allele *2. This study aimed to investigate the relationship of LAPTM4B allelic variation and GBC susceptibility. LAPTM4B genotype was analyzed in 155 healthy individuals and 91 GBC patients by PCR, and the genotypic distribution of LAPTM4B was analyzed with the chi-squared test. The frequency of allele *2 was 37.9 and 24.8% in the GBC and the control groups, respectively, representing a significant difference between these two groups (P < 0.001). LAPTM4B allele *2 may be a risk factor associated with genetic susceptibility to GBC.

BACKGROUND:Lysosomal protein transmembrane 4 beta (LAPTM4B) is a gene related to hepatocellular carcinoma that has two alleles designated LAPTM4B*1 and LAPTM4B*2. This study aimed to investigate the correlation of LAPTM4B genotype with prognosis and clinicopathologic features in patients who have undergone resection for hepatocellular carcinoma (HCC).METHODOLOGY/PRINCIPAL FINDINGS:The LAPTM4B genotype was analyzed by PCR in 68 patients who had undergone curative hepatic resection for hepatocellular carcinoma. The correlation of LAPTM4B genotype with clinicopathologic parameters was assessed with the Chi-squared test. Differences in patient survival were determined by the Kaplan-Meier method. Multivariate analysis of prognostic factors was carried out with Cox regression analysis. Patients with LAPTM4B *2 had both significantly shorter overall survival (OS) and shorter disease-free survival (DFS) (both P<0.001). Multivariate analysis showed that LAPTM4B genotype is an independent prognostic factor for OS and DFS (both P<0.001).CONCLUSIONS/SIGNIFICANCE:Allele *2 of LAPTM4B is a risk factor associated with poor prognosis in patients with resected HCC. LAPTM4B status may be useful preoperatively as an adjunct in evaluation of the operability of HCC.

Background: Lysosomal protein transmembrane 4 beta (LAPTM4B) is a novel cancer-related gene which has two alleles designated LAPTM4B*1 and LAPTM4B*2. In this study we investigated the correlation of LAPTM4B genotype with prognosis and clinicopathologic features in patients who had undergone curative resection for gallbladder carcinoma (GBC).Methodology/Principal Findings: PCR assay was performed to determine the LAPTM4B genotype in 85 patients. The correlation of LAPTM4B genotype with clinicopathologic parameters was assessed with the Chi-squared test. Differences in patient survival were determined by the Kaplan-Meier method. Multivariate analysis of prognostic factors was carried out with Cox regression analysis. Patients with LAPTM4B *2 had both significantly shorter overall survival (OS) and shorter disease-free survival (DFS) (both P < 0.001). Multivariate analysis showed that LAPTM4B genotype is a prognostic factor for OS and DFS (both P < 0.001).Conclusions/Significance: LAPTM4B allele *2 is a risk factor associated with poor prognosis in patients with resected GBC, and LAPTM4B status may be therefore be useful preoperatively as an adjunct in evaluation of the operability of GBC.

Argininosuccinate lyase (ASL) is an important enzyme in the hepatic urea cycle, and catalyzes the reversible reaction of argininosuccinate to arginine and fumarate. Its expression is significantly reduced in some hepatocellular carcinomas (HCC). In this study, we aimed to investigate the correlation of reduced ASL expression and clinicopathologic features and prognosis in HCC patients. Immunohistochemistry was used to determine the expression of ASL in HCC tissues from 61 patients who had undergone hepatic tumor resection. The correlation of ASL expression in HCC with background liver status, viral status, tumor size, portal vein invasion, histopathologic differentiation, early tumor recurrence, sex, and age were assessed with the χ(2) test. Patient survival and survival differences were determined by the Kaplan-Meier method and log-rank test. Cox regression (proportional hazard model) was used for multivariate analysis of prognostic factors. Strong positive staining was found in 39/61 HCCs and normal liver tissues, and reduced ASL staining was found in 22/61 HCCs (36.1%). Patients with low ASL expression had a significantly poorer overall survival and disease-free survival (both P<0.001). Reduced ASL expression in carcinoma tissues was also significantly associated with the tumor-node-metastasis stage and early tumor recurrence, and histopathologic differentiation and portal vein invasion (P<0.05). Cox regression analysis showed that ASL is an independent prognostic marker for HCC. Therefore, reduced ASL expression may be a novel maker for poor prognosis in HCC patients.

PURPOSE:The newly-identified lysosomal protein transmembrane 4 beta-35 (LAPTM4B-35) plays important roles in tumor progression and metastasis, while argininosuccinate synthetase (ASS) provides arginine as an indispensable nutrient for hepatocellular carcinoma (HCC). The present study investigated the clinical significance of the coexpression of LAPTM4B-35 and ASS in HCC patients on determining the prognosis.METHODS:Immunohistochemistry was used to evaluate the expression of LAPTM4B-35 and ASS in HCC tissues and paired noncancerous liver samples from 71 patients. The correlation of combined LAPTM4B-35 and ASS expression with selected clinicopathologic parameters was assessed with the chi-squared test. Patient survival and differences in survival were determined by the Kaplan-Meier method and the log-rank test. A Cox regression analysis was adopted for a multivariate analysis of the prognostic factors.RESULTS:Combined LAPTM4B-35 and ASS expression was significantly associated with TNM stage and portal vein invasion. In addition, patients with HCCs expressing both LAPTM4B-35 and ASS exhibited both markedly poorer overall survival (OS) and disease-free survival (DFS) (both P < 0.001). According to the multivariate analyses, combined LAPTM4B-35 and ASS expression was found to be an independent prognostic factor for OS and DFS (P = 0.039 and P = 0.035, respectively).CONCLUSION:The overexpression of LAPTM4B-35 in combination with positive ASS expression is a negative prognostic marker for HCC.

Hepatocellular carcinoma (HCC) is the leading cause of cancer mortality in many countries. Evaluation of new susceptibility risk factors is therefore warranted in order to explore means to improve the survival rate. Here, we report on a novel HCC-related gene known as lysosomal protein transmembrane 4 beta (LAPTM4B) that has two alleles designated LAPTM4B*1 and LAPTM4B*2. Allele *1 differs from allele *2 in that it contains one copy of a 19-bp sequence, whereas this sequence is duplicated in allele *2 in exon 1 of LAPTM4B. In this study, we aimed to investigate the relationship between LAPTM4B allelic variation and HCC susceptibility. The LAPTM4B genotype was analyzed in the blood samples from 102 HCC patients and 135 healthy individuals by PCR. The genotypic distribution of LAPTM4B was analyzed using the chi-squared test. The frequencies of allele *2 were 38.24 and 24.07% in the HCC group and control group, respectively, representing a significant difference between these two groups (P<0.001). Thus, allele *2 of LAPTM4B appears to be associated with genetic susceptibility of HCC and may therefore be considered as a risk factor.

Lysosomal protein transmembrane 4 beta-35 (LAPTM4B-35) is a tetra-transmembrane glycoprotein that is abundantly localized on membrane-bound organelles including endosomes and lysosomes, and promotes cell proliferation and tumorigenesis through regulation of cell cycle and signaling pathways. The aim of the present study is to determine the potential clinical implications of LAPTM4B-35 expression in hepatocellular carcinoma (HCC).

Background: Lysosomal protein transmembrane 4 β-35 (LAPTM4B-35), a novel oncoprotein that belongs to the mammalian 4-tetratransmembrane spanning protein superfamily, has been implicated in oncogenesis and cancer progression in several solid malignances. However, the expression of LAPTM4B-35 and its role in endometrial cancer progression remain unknown. Materials and Methods: We investigated the expression of the LAPTM4B-35 protein by immunohistochemistry in 30 normal endometrium specimens and 165 endometrial carcinomas and analyzed its correlation with various clinicopathologic features, including patient outcome. Results: LAPTM4B-35 immunoreactivity was overexpressed in endometrial carcinoma cases compared with normal endometrium ( P < 0.001). High LAPTM4B-35 expression was found in 117 (70.91%) of these 165 carcinomas and was positively correlated with the International Federation of Gynecology and Obstetrics stage, histological grade, depth of myometrial invasion, lymph node metastasis, lymph vascular space involvement, and recurrence, but not with age and histological type. Patients with high LAPTM4B-35 expression had significantly poorer overall survival and disease-free survival compared with patients with low expression of LAPTM4B-35 ( P = 0.001 and P = 0.002, respectively). Multivariate analysis showed that high LAPTM4B-35 expression was an independent prognostic factor for both overall survival and disease-free survival of patients with endometrial carcinoma (both P = 0.005). Conclusions: These results showed that high LAPTM4B-35 expression was associated with progression and prognosis of endometrial carcinoma.

LAPTM4B‐35 is a 35‐kDa tetra‐transmembrane protein overexpressed in hepatocellular carcinoma (HCC) and promotes cell survival, proliferation, and tumorigenesis. However, the potential clinical implications of LAPTM4B‐35 in HCC are still unclear. This study is aimed to investigate the correlations between LAPTM4B‐35 expression and prognosis in patients with HCC.

Argininosuccinate synthetase (ASS) has previously been proven to be reductively expressed in hepatocellular carcinoma (HCC) and various types of HCC cell lines. Arginine, the product of ASS, has been used as a target in HCC by recombinant human arginase or arginine deiminase, which is now in the phase II clinical trial stage. This study aimed to present the levels of ASS expression in HCCs and its correlation with clinicopathological features and prognosis of HCC patients. Immunohistochemical detection of ASS was performed on samples from 71 patients with HCC. Positive staining was found in 21 HCCs, with a score of 2, as well as in normal liver tissues. Reduced ASS staining was found in 70.4% (50/71) of HCC tissues, including 21 with a score of 0 and 29 with a score of 1. The staining score in cancer tissues was significantly associated with gender, background liver, histopathological differentiation, recurrence, TNM staging and portal vein invasion (P<0.05), but not with age, viral status, tumor size and serum α-fetoprotein level. Patients with a high ASS expression had significantly poorer overall and disease-free survival (P<0.001 and P<0.001, respectively). These data showed that ASS was reductively or negatively expressed in a large portion of HCC, and that ASS levels in HCCs correlated inversely with prognosis. In conclusion, a high expression of ASS may be a novel marker of poor prognosis of patients presenting with HCC.

Lysosomal protein transmembrane 4 beta ( LAPTM4B ) was originally identified as a hepatocellular carcinoma (HCC)‐associated gene. This gene and its protein product LAPTM4B‐35, are both overexpressed in a variety of human cancers. However, its specific role in cell transformation and malignancy has remained elusive. In the present study we investigated the effects of LAPTM4B‐35 overexpression on the malignant phenotypic features in the HLE cell line. Our data show that overexpression of LAPTM4B‐35 promotes cell proliferation, exogenous growth‐stimulating factor‐independent and anchorage‐independent growth, and enhances metastatic potential, including promotion of both cell migration and invasion. Study of the underlying mechanisms demonstrated alterations of molecular events involved in these processes, which included upregulation of proliferation‐promoting transcription factors such as c‐Myc, c‐Jun, and c‐Fos, and cell cycle‐promoting proteins such as cyclin D1 and cyclin E. In addition, mutagenesis study showed that the PPRP motif in the N‐terminal region of LAPTM4B‐35 plays a critical role in promoting proliferation, migration, and invasion, as well as in the upregulation of the oncoproteins noted above. These data offer insight into the mechanism by which this novel tetratransmembrane protein contributes to the pathogenesis of liver cancer, and suggest that it may be a potential target for cancer therapy. ( Cancer Sci 2009)

Lysosome-associated protein transmembrane 4beta (LAPTM4B) is a member of the mammalian 4-tetratransmembrane spanning protein superfamily, which is strongly expressed in some solid malignancies. The present study investigated the correlation of LAPTM4B expression with clinicopathological features and prognosis in ovarian carcinoma. Expression of LAPTM4B was evaluated semiquantitatively by immunohistochemistry in 85 cases of ovarian carcinoma. High LAPTM4B expression was found in 54 (63.5%) of these 85 carcinomas, and was positively correlated with FIGO stage, histological subtype and residual tumor after primary surgery, but not with age and tumor grade. Patients with high LAPTM4B expression had significantly poorer overall survival (OS) and progression-free survival (PFS) (P<0.001 and P<0.001, respectively) compared to patients with low expression of LAPTM4B. On multivariate analysis, LAPTM4B expression was found to be an independent prognostic factor for OS and PFS (P=0.01 and P=0.03, respectively). These results showed that high LAPTM4B expression was associated with progression of ovarian carcinoma and correlated with unfavorable clinical outcome, suggesting that LAPTM4B may be a clinically useful prognostic indicator for ovarian carcinoma.